Ticks, Mites, and Lice Flashcards
Lyme Disease vector and geography
Ixodes tick
NE and MW USA
The Ixodes tick also serves as the vector for . . .
Lyme
Anaplasmosis
Babesiosis (Babesia microti)
Borrelia miyamotoi, (fever and meningoencephalitis)
When treating Lyme w/ Doxycycline offers the advantage of treating possible . . .
Anaplasma phagocytophilum.
Dx of CNS-Lyme infection . . .
Positive results on serologic testing
Intrathecal antibody production or B. burgdorferi PCR on CSF
Erythema migrans W / O travel to an area endemic for Lyme disease.
Southern tick–associated rash illness (STARI)
Results of labs testing for B. burgdorferi are invariably negative
Most prevalent in SE and SC USA
Disseminated infection has not been documented.
Babesiosis infects . . .
erythrocytes
Babesia microti is transmitted by . . .
Ixodes tick
and cases by transfusion of infected blood products
High risk patients w/ higher Babesia parasitic burdens . . .
Asplenia or those who are
older patients
Immunocompromised
Babesia lab findings and blood smear
. . .
Laboratory findings are related to hemolysis
Transaminitis and thrombocytopenia are also common.
Giemsa or Wright staining, Trophozoites appear as ring forms inside erythrocytes (may be confused with malaria)
Protozoa may resemble a tetrad or Maltese cross formation.
PCR is a more sensitive test
Treatment for babesiosis . . .
Mild - mod disease: atovaquone plus azithromycin
Severe disease: clindamycin plus quinine
Exchange transfusion can be considered
The vector for ehrlichiosis (HME) and geography . . .
Lone Star tick,
Endemic to the southcentral and southeastern of US
Laboratory abnormalities raising suspicion for HME and HGA ?
Leukopenia + thrombocytopenia.
Transaminitis w/ normal bili and AlkP
Morulae, basophilic inclusion bodies composed of clusters of bacteria, may be found in leukocyte cytoplasm
Tx for HME and HGA ?
Doxycycline
Treatment options are limited, so desensitization may be required.
Consider diagnosis of RMSF:
Any patient with a fever and possible tick exposure regardless of the presence of a rash
Dx of acute RMSF
Immunohistochemistry or PCR of a skin biopsy
Tx for RMSF
Doxycycline;
Contraindicated in pregnancy; chloramphenicol is an alternative option
• Scrub typhus
• Orientia tsutsugamushi
• Louse-borne relapsing fever
• Borrelia recurrentis
• Tick-borne relapsing fever
Ornithodorus ticks
- Borrelia hermsii
* Borrelia turicatae
• Boutonneuse (Mediterranean) fever
• Rickettsia conorii
• Louse-borne epidemic typhus
• Rickettsia prowazekii
• Endemic (murine) typhus
• Rickettsia typhi
American Boutonneuse Fever
Skin findings and pathogen
Rickettsia parkeri
Lone Star or Gulf Coast ticks
- Faint salmon-colored rash
- Single or multiple eschars
African Tick Bite Fever
Rickettsia africae
- Clusters of cases, multiple eschars
- Incubation period 6-7d
Rickettsialpox
• R. akari
Vector • Mouse mites
- Single eschar
- Rash 20-40 papulovesicles
Scrub Typhus
• O. tsutsugamushi
Vector • Trombiculid mite (chiggers)
• Triangle Japan - Australia - Russia
- Eschar, painful/draining lymph nodes, rash, delirium
- May progress to multiorgan system failure
If I say “flying squirrel”
You say “epidemic typhus” or “R. prowazekii”
Typhus: Two Forms
Epidemic - R. prowazekii
Endemic - R. typhi
Epidemic Typhus - R. prowazekii
Louse (body, head)
War refugees, crowded conditions/poor hygiene
Lethal
Pearl: most common cause of blood transfusion related parasite infection in US
Babesia microti
PCR for Dx
Tickborne Relapsing Fever US pearls . . .
- mainly B. hermsii
- Elevation 1500-8000 feet
- Can be severe : ARDS
- Spirochetes seen in blood smear
- Jarisch Herxheimer reaction in 54%
Louse-borne Relapsing Fever (LBRF) pearls . . .
Borrelia recurrentis
Vector: Human body louse
(Refugee camps, famine, natural disasters)
Borrelia miyamotoi
Epidemiology = Lyme disease
see in in Minnesota and Wisconsin
Tick-borne viruses
- Powassan (Deer Tick Virus Lineage II, flavivirus)
- Colorado tick fever (colitvirus)
- Heartland virus (phlebovirus) = HME
- Bourbon virus (?)
and
• Tularemia
RMSF Rash:
Can appears after several days of fever and viral-like prodrome
• Blood smear: may be helpful in
- Morulae: PMN = Anaplasma, Monocyte = Ehrlichia
- Spirochete: relapsing fever Borrelia or B. miyamotoi
- Erythrocyte inclusions: Babesia
• Rodent infested urban house:
• Rickettsialpox
Lyme Borreliosis
Europe
• Borrelia afzelii & Borrelia garinii»_space;
Erythema migrans: classic and MoCo
Most common: homogeneous, pink-red ovoid
> 5cm = more secure diagnosis
Late Lyme disease (3): Dermatologic
Acrodermitis chronica atrophicans (Europe) (foot?)
Borrelia Lymphocytoma (Europe) (ear?)
Diagnostics: Lyme arthritis
Synovial fluid:
o 10,000-25,000 WBC
o PMN predominant
Borr burg PCR
• Serology: ~100% (+) in blood
High titer, Bb IgG immunoblot
• Second generation B. Burgdorferi Ab assays:
C6 or VlsE (variable major protein-like sequence expressed)
Better at detecting B. garinii, B. afzelli (Europe)
Treatment: Late Lyme arthritis
• Initial treatment: x 28d
If lack of response: second course
• ~10% do not respond to repeated antibiotic therapy = Abx-refractory Lyme arthritis
oAutoimmune phenomenon,
Treatment: DMARDs, intra-articular corticosteroids, synovectomy
I. scapularis tick bite prophylaxis
Doxy *200 mg given with 72h of tick bite
